This invention relates generally to devices for transmitting power from an input source to an output source and more particularly concerns a device for varying the rotational speed ratio between input and output sources.
There are many variable transmissions currently in use for receiving input at a first rotational speed and converting it to output at a second rotational speed. Hydraulic pump or turbine transmissions are costly, complicated and generally inefficient. Split pulley transmissions are generally able to handle relatively low power systems but lose much of their input energy to friction between their pulleys and V-belt. Flat drive plate transmissions also have power input limitations and high frictional power loss. Known positive gear engagement transmissions such as described and illustrated in U.S. Pat. No. 5,360,380, suffer from a variety of limitations. They do not provide an infinite number of ratios to choose from and, therefore, must be shifted in synchronization with an interruption in power, resulting in a jerking motion. Synchronization is necessary to avoid mashing planet gear teeth while the diameter of the ring member is changed so as to change ratios. Timing cams or solenoids could be used for synchronization, but high speed operation requires many components which reduce the cost effectiveness and increase the maintenance requirements of the system. My present U.S. Pat. No. 6,132,330 uses positive gear engagement to transmit power from an input to an output at continuously variable speeds but requires a highly modified input planetary drive gear of a resilient nature not common in conventional engineering.
It is, therefore, an object to the present invention to provide a positive gear engagement transmission which is more reliable than known transmissions. Another object of this invention is to provide a positive gear engagement transmission which greatly reduces loss in power due to friction. A further object of this invention is to provide a positive gear engagement transmission with a continuum of selectable gear ratios with smooth transition from one ratio to the next. It is also an object of this invention to provide a positive gear engagement transmission which minimizes the typical slippage problems associated with non-positive gear engagement drive systems. Still another object of this invention is to provide a positive gear engagement transmission with a continuously variable ratio between the input linear or rotational speed and the output speed, which may be varied continuously. Yet another object of this invention is to provide a positive gear engagement transmission which uses conventional gears without radical modification.